Expression of Serum and Exosomal microRNA-34a in Subjects with Increased Fat Mass.

miR-34a expression negatively correlated with multiple cardiometabolic risk markers in both serum and exosomes.

• Negative correlations were found with Total Cholesterol, Triglycerides, LDLc/HDLc ratio, TG/HDLc ratio, BMI, and body adiposity.
• Additional negative correlations included C3, CRP, fasting insulin, HOMA-IR, HOMA-B, Chemerin, CCL2, AdipoQT, and AdipoQ-H.
• miR-34a expression correlated positively with HDLc and QUICKI, both markers of favorable metabolic status.
• Study population included 142 adults with mean age 36 ± 11 years, classified by body fat percentage (≥25% in men, ≥35% in women).

Serum miR-34a levels were higher than exosomal miR-34a levels overall.

• The difference in miR-34a abundance between compartments was noted as a consistent pattern across the study population.
• Exosomes were isolated using Invitrogen® kit and characterized by cryo-TEM to confirm vesicle identity.
• miR-34a expression was quantified by qRT-PCR in both serum and circulating extracellular vesicles.
• The authors interpreted this difference as potentially reflecting selective packaging or differential release of miR-34a into exosomes versus free circulation.

LDLc, sdLDLc, sdLDLc/LDLc ratio, TC/HDLc ratio, and fasting glucose showed opposite correlation patterns with miR-34a between serum and exosomal compartments.

• These five markers displayed divergent directional correlations depending on whether serum or exosomal miR-34a was assessed.
• This finding suggests that the compartment-specific packaging of miR-34a into exosomes may differentially reflect distinct aspects of lipid and glucose metabolism.
• The opposite correlation patterns were notably observed for small dense LDL particles (sdLDLc) and their ratio to total LDL.
• This compartment-specific divergence was highlighted as a notable finding distinguishing the two biomarker sources.

Adipocyte-derived extracellular vesicles (AdEVs) and their microRNA cargo were characterized as key mediators of metabolic homeostasis and obesity-related dysfunction.

• Exosomes were identified as a subtype of extracellular vesicles that transport biomolecules including nucleic acids, lipids, and proteins.
• AdEVs were described as playing a crucial role in maintaining metabolic homeostasis and implicated in obesity-related dysfunction.
• microRNAs were described as regulating post-transcriptional gene expression and participating in immunometabolic regulation.
• The study framed miR-34a as a candidate non-invasive biomarker of adipose tissue dysfunction based on its presence in circulating exosomes.

The study classified subjects by body fat percentage thresholds of ≥25% in men and ≥35% in women to define increased fat mass.

• A total of 142 adults were enrolled, with a mean age of 36 ± 11 years.
• Body fat percentage thresholds were sex-specific: ≥25% for men and ≥35% for women.
• Exosome isolation was performed using the Invitrogen® platform and vesicles were characterized by cryo-transmission electron microscopy (cryo-TEM).
• miR-34a quantification was performed by quantitative reverse transcription PCR (qRT-PCR) in both serum and isolated exosome fractions.